Transmitting apparatus, receiving apparatus and signal processing method thereof

ABSTRACT

A method for generating a packet of transmitting apparatus is provided. The method includes: setting a value of a Deleted Null Packet (DNP) counter to zero; increasing the value for each deleted null packet preceding a non-null transport stream (TS) packet; and generating a packet comprising a header and a payload, wherein the header includes a DNP field, the payload includes the non-null TS packet, and the value of the DNP counter is used to set the DNP field.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 15/905,225 filedFeb. 26, 2018, which is a continuation of U.S. application Ser. No.15/385,016 filed Dec. 20, 2016, which is a continuation of U.S.application Ser. No. 14/337,435 filed Jul. 22, 2014, which claimspriority from Korean Patent Application No. 10-2014-0054762, filed onMay 8, 2014 in the Korean Intellectual Property Office, and U.S.Provisional Application Nos. 61/861,016, 61/873,470, and 61/856,909,filed Aug. 1, 2013, Sep. 4, 2013 and Jul. 22, 2013, respectively, thedisclosures of which are incorporated herein by reference in theirentirety.

BACKGROUND 1. Field

Apparatuses and methods consistent with exemplary embodiments of theinventive concept relate to a transmitting apparatus, a receivingapparatus, and a signal processing method thereof, and morespecifically, to a transmitting apparatus configured to map and transmitdata with one or more signal processing paths, the receiving apparatus,and the signal processing method thereof.

2. Description of the Related Art

In the information society of the 21st century, broadcastingcommunication services embrace the emergence of digitization,multichannel distribution, wideband establishment, and high-qualityproduction. Specifically, as the distribution and use of high-qualitydigital television (TV), portable medial player (PMP), and mobiledevices explode, digital broadcasting services meet increasing demandsfor supporting various receiving methods.

To meet such demands, standardization groups designate variousstandards, and provide various services to meet user needs. Thus, amethod is necessary, which can provide better services with moreenhanced performances.

SUMMARY

One or more exemplary embodiments of the present inventive concept mayovercome the above disadvantages and other disadvantages not describedabove. However, the present inventive concept is not required toovercome the disadvantages described above, and exemplary embodiments ofthe present inventive concept may not overcome any of the problemsdescribed above.

One or more exemplary embodiments are provided considering the currentsituation in which standardization groups designate various standardsand provide various services to meet user needs.

According to an aspect of an exemplary embodiment, there is provided atransmitting apparatus which may include: a baseband packet generatorconfigured to generate a baseband packet including a header and payloaddata corresponding to an input stream; a frame generator configured togenerate a frame including the baseband packet; a signal processorconfigured to process the generated frame; and a transmitter configuredto transmit the processed frame, wherein the header includes informationabout whether a number of null packets deleted when generating thebaseband packet is more than a predetermined number, information about anumber of packets within the baseband packet, and information about anumber of the deleted null packets.

The input stream may be a transport stream.

Further, the header may include information about an input stream clockreference (ISCR) related with the baseband packet.

Further, the header may include a base header and an option header. Thebase header may include the information about whether the number of nullpackets deleted when generating the baseband packet is more than thepredetermined number, the information about the number of the packetswithin the baseband packet, and the information about the number of nullpackets less than the predetermined number, and the option header mayinclude the ISCR information and information about a number of nullpackets exceeding the predetermined number when the number of thedeleted null packets is more than the predetermined number.

Further, the base header may include one (1) byte field, and the one (1)byte field may include a one (1) bit field indicating whether the numberof null packets deleted when generating the baseband packet is more thanthe predetermined number, a four (4) bit field indicating the number ofthe packets, and a three (3) bit field indicating information about thenumber of null packets less than the predetermined number.

Further, the option header may include a 24 bit field indicating theISCR information and an eight (8) bit field indicating information aboutthe number of null packets exceeding the predetermined number when thenumber of the deleted null packets is more than the predeterminednumber.

Further, the frame including the baseband packet may be a basebandframe, and the signal processor may generate a transmitting frame byprocessing the baseband frame and mapping the input stream with one ormore signal processing paths.

According to an aspect of another exemplary embodiment, there isprovided a receiving apparatus configured to receive data from atransmitting apparatus which maps the data included in an input streamwith one or more signal processing paths and transmits the same. Thisreceiving apparatus may include: a receiver configured to receive aframe comprising the data; and a signal processor configured to extractheader information from a baseband packet included in the frame andprocess payload data included in the baseband packet based on the headerinformation, wherein the header information comprises information aboutwhether a number of null packets deleted when generating the basebandpacket is more than a predetermined number, a number of the packetswithin the baseband packet, and a number of the deleted null packets.

The input stream may be a transport stream.

Further, the header information may include the ISCR information.

Further, the header may include a base header and an option header. Thebase header may include the information about whether the number of nullpackets deleted when generating the baseband packet is more than thepredetermined number, the information about the number of the packetswithin the baseband packet, and the information about the number of nullpackets less than the predetermined number, and the option header mayinclude the ISCR information and information about a number of nullpackets exceeding the predetermined number when the number of thedeleted null packets is more than the predetermined number.

Further, a signal processing method of a transmitting apparatus mayinclude: generating a baseband packet comprising a header and payloaddata corresponding to an input stream; generating a frame comprising thebaseband packet; processing the generated frame; and transmitting theprocessed frame, wherein the header comprises information about whethera number of null packets deleted when generating the baseband packet ismore than a predetermined number, information about a number of packetswithin the baseband packet, and information about a number of thedeleted null packets.

The input stream may be a transport stream.

Further, the header may include the ISCR information.

Further, the header may include a base header and an option header. Thebase header may include the information about whether the number of nullpackets deleted when generating the baseband packet is more than thepredetermined number, the information about the number of the packetswithin the baseband packet, and the information about the number of nullpackets less than the predetermined number, and the option header mayinclude the ISCR information and information about a number of nullpackets exceeding the predetermined number when the number of thedeleted null packets is more than the predetermined number.

Further, the base header may include one (1) byte field, and the one (1)byte field may include a one (1) bit field indicating whether the numberof null packets deleted when generating the baseband packet is more thanthe predetermined number, a four (4) bit field indicating the number ofthe packets, and a three (3) bit field indicating information about thenumber of null packets less than the predetermined number.

Further, the option header may include a 24 bit field indicating theISCR information and an eight (8) bit field indicating information aboutthe number of null packets exceeding the predetermined number when thenumber of the deleted null packets is more than the predeterminednumber.

Further, the frame including the baseband packet may be a basebandframe, and the signal processor may generate a transmitting frame byprocessing the baseband frame and mapping the input stream with one ormore signal processing paths.

According to an aspect of another exemplary embodiment, there isprovided a signal processing method of a receiving apparatus to receivedata from a transmitting apparatus which maps the data included in aninput stream with one or more signal processing paths and transmits thesame. This method may include: receiving a frame including the data; andextracting header information from a baseband packet included in theframe and process payload data included in the baseband packet based onthe header information, wherein the header information includesinformation about whether a number of null packets deleted whengenerating the baseband packet is more than a predetermined number, anumber of the packets within the baseband packet, and a number of thedeleted null packets.

The input stream may be a transport stream.

Further, the header may include the ISCR information.

Further, the header may include a base header and an option header. Thebase header may include the information about whether the number of nullpackets deleted when generating the baseband packet is more than thepredetermined number, the information about the number of the packetswithin the baseband packet, and the information about the number of nullpackets less than the predetermined number, and the option header mayinclude the ISCR information and information about a number of nullpackets exceeding the predetermined number when the number of thedeleted null packets is more than the predetermined number.

According to the above various exemplary embodiments, a data processingefficiency can be enhanced because an input stream may be efficientlymapped with a physical layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects of the present inventive concept will bemore apparent by describing certain exemplary embodiments of the presentinventive concept with reference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a transmitting system according to anexemplary embodiment;

FIG. 2 illustrates an example of input processing block illustrated inFIG. 1, according to an exemplary embodiment;

FIGS. 3A to 3D are provided to explain a unit constitution of atransmitting frame according to an exemplary embodiment;

FIG. 4 is a block diagram of a transmitting apparatus according to anexemplary embodiment;

FIG. 5A is a detailed block diagram of a frame generator according to anexemplary embodiment;

FIG. 5B illustrates a baseband packet, a baseband frame and a scrambledbaseband frame according to an exemplary embodiment;

FIG. 6A is a view provided to explain a method for deleting a nullpacket according to an exemplary embodiment;

FIG. 6B illustrates a baseband packet format according to an exemplaryembodiment;

FIGS. 7A to 7D illustrate baseband packet formats according to otherexemplary embodiments;

FIGS. 8A to 8D illustrate baseband packet formats according to otherexemplary embodiments;

FIGS. 9A to 9H illustrate baseband packet formats according to otherexemplary embodiments;

FIG. 10 is a view provided to briefly explain a case of applying a TSmode adaptation according to various exemplary embodiments;

FIG. 11A is a block diagram of a receiving apparatus according to anexemplary embodiment;

FIG. 11B is a block diagram provided to explain in detail a signalprocessor according to an exemplary embodiment;

FIG. 12 is a flowchart provided to explain in detail a signal processingmethod of a transmitting apparatus according to an exemplary embodiment;

FIG. 13 is a flowchart provided to explain a signal processing method ofa receiving apparatus according to an exemplary embodiment;

FIG. 14 is a block diagram of a receiver according to an exemplaryembodiment;

FIG. 15 is a detailed block diagram of a demodulator 1230 of FIG. 14according to an exemplary embodiment; and

FIG. 16 is a flowchart provided to briefly explain operations of areceiver from a time point when a user selects a service to a time pointwhen the selected service is played, according to an exemplaryembodiment.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Certain exemplary embodiments of the inventive concept will now bedescribed in greater detail with reference to the accompanying drawings.

In the following description, same drawing reference numerals are usedfor the same elements even in different drawings. The matters defined inthe description, such as detailed construction and elements, areprovided to assist in a comprehensive understanding of the exemplaryembodiments. Accordingly, it is apparent that the exemplary embodimentscan be carried out without those specifically defined matters. Also,well-known functions or constructions are not described in detail sincethey would obscure the invention with unnecessary detail.

FIG. 1 is a block diagram of a transmission system according to anexemplary embodiment.

Referring to FIG. 1, the transmission system 1000 may include an inputprocessing block 1100, a Bit Interleaved Coding and Modulation (BICM)block 1200, a structure block 1300 and an OFDM waveform generator block1400.

The input processing block 1100 generates a BBFRAME (baseband frame)from an input stream of data to be served. The input stream may be atransport stream (TS), an Internet protocol (IP), e.g., IPv4, IPv6,stream, an MPEG media transport) (MMT) stream, a generic stream (GS), ora generic stream encapsulation (GSE) stream.

The BICM block 1200 determines a forward error correction (FEC) codingrate and a constellation order according to area through which data tobe served are transmitted, e.g., (fixed PHY frame or mobile PHY frame),and performs encoding and time interleaving. Meanwhile, signalinginformation about data to be served may be encoded through a separatelyprovided BICM encoder (not illustrated) or encoded by the BICM encoder1200.

The structure block 1300 generates a transmission frame by combining thetime-interleaved data with signaling information.

The orthogonal frequency-division multiplexing (OFDM) waveform generatorblock 1400 generates OFDM signals on a time domain corresponding to thegenerated transmission frame, modulates the generated OFDM signals intoradio frequency (RF) signals, and transmits the RF signals to areceiver.

The signaling information combined with data in the structure block 1300may include information about an input type of the input stream which isinput to the input processing block 1100 and other various pieces ofinformation, according to an exemplary embodiment. Various exemplaryembodiments will be explained in detail below by referring to drawings.

FIG. 2 illustrates an exemplary embodiment of the input processing block1100 illustrated in FIG. 1.

Referring to FIG. 2, the input processing block 1100 includes a basebandpacket (BBP) construction block 1100 and a baseband frame constructionblock 1200. The baseband packet construction block 1100 generates abaseband packet from the input stream such as an IP stream. At thisprocess, a TS stream may not be converted to a baseband packet format,and thus, a TS packet constituting a TS stream may correspond to abaseband packet. The baseband frame construction block 1120 generates abaseband frame from the input baseband packets.

FIGS. 3A to 3D are provided to explain a structure of a transmissionframe according to exemplary embodiments.

Referring to FIG. 3A, input processing to process the input stream to bea baseband frame may operate at a data pipe level.

FIG. 3A illustrates a process wherein the input stream is processed tobe a baseband frame. A plurality of input streams 311 to 313 areprocessed to be data pipes 321 to 323 of a plurality of baseband packetsthrough input pre-processing, and the data pipes 321 to 323 of theplurality of baseband packets are encapsulated to be data pipes 331 to333 of a plurality of baseband frames through input processing (See FIG.1, the input processing block 1100), and scheduled to be transmissionframes.

FIG. 3B is a view provided to explain relations between a basebandpacket 320 and a baseband frame 330. A payload of the baseband packet320 is a packet constituting a TS stream and/or another type of stream.Further, the baseband frame 330 may include a plurality of basebandpackets or a part of the plurality of baseband packets which may includea fragmented baseband packet.

FIG. 3C is a view provided to explain a local frame constitutionregarding each physical layer pipe (PLP). The PLP in the presentembodiment may correspond to a PLP defined in the Second GenerationDigital Terrestrial Television Broadcasting System (DVB-T2) standard.

Referring to FIG. 3C, the baseband frame 330 includes a header, a datafield and a padding field.

The baseband frame 330 is processed to be a baseband frame FEC packet340 by adding parities through an FEC encoding process.

The baseband frame FEC packet 340 is processed to be an FEC block 350through a bit-interleaving and constellation mapping process, aplurality of FEC blocks are processed to be time-interleaving blocks 360through a cell-interleaving process, and a plurality oftime-interleaving blocks constitute an interleaving frame 370.

FIG. 3D is a view provided to explain constitution of an interleavingframe.

Referring to FIG. 3D, the interleaving frame 370 may be transmittedthrough different transmission frames 361, 362, and a plurality oftransmission frames and at least one future extension frame (FEF) partmay constitute one super frame 370.

Meanwhile, one transmission frame 361 may be constituted with a preamblesymbol 10 and a data symbol 20 which transmits data.

The preamble symbol 10 includes an L1 pre-signaling area 11 and an L1post-signaling area 12. The L1 pre-signaling area 11 may provide basictransmission parameters including parameters requested for receiving anddecoding L1 post-signaling, and have a fixed length.

The L1 post-signaling area 12 includes a configurable field 12-1 and adynamic field 12-2.

The configurable field 12-1 includes information that may differ bysuper frame unit, and the dynamic field 12-2 includes information thatmay differ by transmission frame unit. Relations with a super frame anda transmission frame will be explained below in detail.

Further, the L1 post-signaling area 12 may selectively include anextension field 12-3. Further, although not illustrated in FIG. 3D, theL1 post-signaling area 12 may further include a cyclic redundancy check(CRC) field and an L1 padding field.

FIG. 4 is a block diagram of a transmitting apparatus 100 according toan exemplary embodiment.

Referring to FIG. 4, the transmitting apparatus 100 includes a basebandpacket generator 110, a frame generator 120, a signal processor 130 anda transmitter 140.

The baseband packet generator 110 may generate a baseband packet (or L2packet) which includes a header and payload data based on an incomingstream. The header may include information about the payload dataincluded in the baseband packet and information about a packet includedin the baseband packet. More descriptions about the baseband packet willbe provided in a later part of the specification.

The payload data included in the baseband packet may include any one ofan IP packet, a TS packet and a signaling packet, or a combination oftwo or more of the foregoing packets. However, data included in thepayload data are not limited to the above, and instead, various types ofdata may be included. The baseband packet may be considered as a unitpacket necessary for mapping various types of incoming data with aphysical layer. The payload data included in the baseband packetaccording to an exemplary embodiment may include a TS packet only, whichwill be explain in detailed in a later part of the specification.

The frame generator 120 may generate a frame including the basebandpacket. The generated frame may be a baseband frame (or L1 packet)including the baseband packet.

The frame generator 120 may generate the baseband frame in a sizeconsidering a FEC code by arranging a plurality of baseband packetsincluding an IP packet and a header. The baseband packet according to anexemplary embodiment may be a TS packet; however, the same process maybe applied to various types of data as well as the TS packet. Processesof generating the baseband packet and the baseband frame will be explainin detailed with FIGS. 5A and 5B.

FIG. 5A is a detailed block diagram of a frame generator according to anexemplary embodiment.

Referring to FIG. 5A, the frame generator 120 may include a basebandheader generator 120-1 and a baseband frame generator 120-2. Further,the baseband frame generator 120 may generated and transmit the basebandframe to a baseband frame scrambler 125.

The baseband packet generator 110 may generate the baseband packet inorder to transmit an incoming IP packet, TS packet and other varioustypes of data toward respective PLPs with regard to input modes. Thebaseband packet corresponds to an L2 packet of the ISO 7 layer model.Thus, the baseband packet generator 110 may generate the baseband packetby encapsulating incoming packets (IP packet, TS packet) from upperlayers than the Layer 2.

The baseband header generator 120-1 may generate a header inserted intothe baseband frame. The header inserted into the baseband frame iscalled as a baseband header, and the baseband header includesinformation about the baseband frame.

When an incoming stream is a TS, the baseband header generator 120-1 maygenerate the baseband header including information about a number of TSpackets within a baseband packet and a number of removed null packets.In addition, the baseband header generated by the baseband headergenerator 120-1 may include various pieces of information, which will bedescribed below.

Further, the baseband frame generator 120-2 may generate the basebandframe by encapsulating the baseband header generated from the basebandheader generator 120-1 with at least one baseband packet outputted fromthe baseband packet generator 110.

Further, the baseband frame scrambler 125 may randomly scramble datastored in the baseband frame before FEC codes are added to each of thebaseband frame, and generate a scramble baseband frame. The scrambledbaseband frame is transmitted through a PLP. One PLP may be constitutedwith baseband frames each having a fixed size. Thus, an incoming streammay be encapsulated into a baseband frame for one PLP.

The PLP indicates a signal path which is independently processed. Thus,each service (e.g., video, extended video, audio and data) may betransmitted and received through a plurality of RF channels. The PLP isa signal path where these services are transmitted or a streamtransmitted through this signal path. Further, the PLP may be positionedon slots which are distributed with a time interval on a plurality of RFchannels, or may be distributed with a time interval on one RF channel.Thus, one PLP may be distributed and transmitted with a time interval onone RF channel or on a plurality of RF channels.

The PLP structure is configured of an input mode A for providing one PLPand an input mode B for providing a plurality of PLPs. When the inputmode B is supported, a service may be provided more robustly. Further, alength of time-interleaving increases by transmitting one stream in adistributed manner, and thus, the time diversity gain can be obtained.Further, when reception of only a specific stream is required, areceiver may be turned off during the time of receiving streams otherthan the specific stream. Thus, this PLP structure is proper forproviding mobile and moving broadcasting services because a mobile orhandheld device may have a low electrical power capacity.

The time diversity is a technology which combines a plurality ofreceiving signals and obtains a better transmission quality at areceiving end when the same signal is transmitted several times with acertain time interval from a transmitting end in order to reducedeterioration of a transmission quality in a mobile communicationchannel.

Further, transmission efficiency can increase by including information,that can be commonly transmitted through a plurality of PLPs, in one PLPand transmitting this information through one PLP. A PLP0 performs theabove function; this PLP is called a common PLP. PLPs other than thePLP0 may be used for transmitting data; these PLPs are called a dataPLP. When the common PLP and the data PLP are used, a standarddefinition television (SDTV) service and a high definition television(HDTV) service for a same program may be provided to a mobile device anda fixed device, respectively. Further, various broadcasting services canbe provided to users through broadcasting stations and broadcastingcontents providers, and further, distinguished broadcasting services canbe provided and received at fringe areas where reception of broadcastingservices is difficult.

Meanwhile, FIG. 5B illustrates a baseband packet, a baseband frame, anda scramble baseband frame according to an exemplary embodiment.

Referring to FIG. 5B, when the baseband packet generator 110 generates aplurality of baseband packets 111, 112 by storing at least one TS packetin a baseband packet payload and inserting a header, the frame generator120 may generate a plurality of baseband frames 121, 122 by grouping aplurality of the baseband packets 111, 112 and inserting a basebandheader. Each of the baseband frames 121, 122 may include a plurality ofbaseband packets, and further, a part of the baseband packets which mayinclude a fragmented baseband packet.

The baseband frame scrambler 125 may generate a plurality of scrambledbaseband frames 125-1, 125-2 by randomly scrambling the baseband frames121, 122. Further, the scrambled baseband frames 125-1, 125-2 may betransmitted to at least one PLP as described above, andsignal-processing to add FEC codes may be performed.

Referring to FIG. 4 again, the signal processor 130 may signal-processthe scrambled baseband frames. According to another exemplaryembodiment, the baseband frames generated at the frame generator 120 maynot be scrambled before being transmitted to the PLP.

Specifically, the signal processor 130 may signal-process the basebandframe and generate a transmission frame. The transmission frame mayindicate the transmission frames 361, 362 illustrated in FIG. 3D.

Further, the signal processor 130 may insert signaling information intoa signaling area of the baseband frame. The signaling information may beL1 (Layer 1) signaling signals transmitting L1 signals for framesynchronization. The preamble 10 in which L1 signaling information isinserted may include the L1 pre-signaling area 11 and the L1post-signaling area 12, as illustrated in FIG. 3D. Further, the L1post-signaling area 12 includes the configurable field 12-1 and thedynamic field 12-2.

Meanwhile, the L1 pre-signaling area 11 may include information foranalyzing the L1 post-signaling and information about a whole system.The L1 pre-signaling area may be configured to have a same length.Further, the L1 post-signaling area 12 may include information abouteach PLP and information about the system. Although the L1 signalingarea included in each frame, i.e., a baseband frame, within one superframe 370 (see FIG. 3D) has a same length, information included thereinmay be different from one another.

The signaling information may include information about an input type ofan incoming stream and information about a type of data mapped with oneor more signal processing paths.

The information about an input type may indicate whether every signalprocessing path within a frame is a same input type or not.

The information about an input type may include information about atleast one of a first input type in which every signal processing pathtransmits only a first type stream on a single mode, a second input typein which every signal processing path transmits the first type streamand a second type stream in a combination mode, a third input type inwhich every signal processing path transmits a third type streamdifferent from the first type stream in the combination mode, and afourth input type in which at least two signal processing paths transmitdifferent types of stream.

The first type stream may be a TS stream, the second type stream may beIP stream, and the third type stream may be a stream different from theTS stream and the IP stream.

The signaling information may further include at least one ofinformation about whether to use mode adaptation and information aboutan Input Stream Synchronizer (ISSY) mode, when one or more signalprocessing paths includes a TS stream.

The information about an input type of an incoming stream may beincluded in the L1 pre-signaling area 11 and the information about atype of data may be included in the L1 post-signaling area 12. Theinformation about a type of data may be included in the configurablefield 12-1.

The signal processor 130 may perform functions corresponding to those ofthe BICM block 1200 and the structure block 1300 illustrated in FIG. 1.

The transmitter 140 may transmit the signal-processed frame to atransmitting apparatus (not illustrated). Here, the signal-processedframe may indicate the transmission frames 361, 362 illustrated in FIG.3D.

The transmitter 140 may perform function corresponding to those of theOFDM waveform generator block 1400 illustrated in FIG. 1. Thus, thetransmitter 140 performs modulation to modulate a frame generated at theframe generator 120 and processed at the signal processor 130 into RFsignals, and transmit the RF signals to a receiving apparatus (notillustrated).

A method for deleting a null packet according to an exemplary embodimentand a baseband packet format or configuration will be explained below indetail.

FIG. 6A illustrates a method for deleting a null packet according to anexemplary embodiment.

A TS rule requests that a bit rate should be maintained regardless oftime change when outputting in a multiplexer of a transmitting apparatusand a demultiplexer of a receiving apparatus, and an end-to-end delayshould also be maintained. Regarding some incoming TS signals, a certainamount of null packets may be generated in order to accommodate avariable bit rate service in a certain bit rate streams. In this case,TS null packets may be distinguished (PID=8191) and deleted in order toavoid an unnecessary transmission overhead. The above deleting may beperformed by a method in which the deleted null packets can be insertedagain on the positions where they are placed at a receiving apparatus.Thus, a certain amount of bit rates can be secured and necessity ofupdating a Program Clock Reference (PCR) timing stamp can be reduced.

When a null packet is deleted as illustrated in FIG. 6A, a TS packet(i.e., a TS packet of PID≠8191) is transmitted without a null packet(i.e., a TS packet of PID=8191).

A counter called as a Deleted Null Packet (DNP) is first reset beforetransmitting a baseband packet. At this time, the deleted null packetsdisposed prior to consecutive valid TS packets in the baseband packetare counted. When the DNP reaches a predetermined maximum value, a nullpacket disposed prior to the TS packets is considered to be a validpacket and transmitted.

The maximum DNP value may vary according to a format of a basebandpacket. For example, if the format is set to transmit a TS stream onlythrough a same PLP, the DNP has a maximum length of 11 bits (see FIG.6B), and thus, the maximum value becomes 2047.

FIG. 6B illustrates a baseband packet format according to an exemplaryembodiment.

FIG. 6B illustrates a baseband packet format when an incoming stream ofa PLP is constituted with a TS stream only according to an exemplaryembodiment.

Referring to FIG. 6B, when an incoming stream includes a TS stream only,a base header 611 of a baseband packet 610 includes an NPDI field 611-1,an NUMTS field 611-2 and a DNPS field 611-3.

The NPDI field 611-2 indicates a relative length of a DNP counter, andmay be implemented by one (1) bit field. If more than eight (8) nullpackets prior to TS packets are deleted when generating a basebandpacket, the NPDI field may be set to “1”. In this case, a number ofdeleted null packets may be provided by combining the DNPS field 611-3(3 LSB bits) of the base header 611 and a DNPL field 612-1 (8 MSB bits)of an option header 612 which will be described below. If less thaneight (8) null packets prior to TS packets are deleted when generating abaseband packet, the NPDI field may be set to “0”, and the number of thedeleted null packets may be provided in the DNPS field 611-3 (3 LSBbits).

The NUMTS field 611-2 indicates the number of TS packets within abaseband packet, i.e., the number of TS packets in a current group of TSpackets, and may be implemented by a four (4) bit field. NUMTS=“0”indicates that 16 packets are transmitted within a baseband packet, andthe other values may indicate the number of TS packets. For example,NUMTS=“1” indicates that one TS packet is transmitted. Therefore, up to16 TS packets may be transmitted within one baseband packet, i.e.,within one packet group. For another example, NUMTS may be expressed byone (1) less than the number of TS packets within a baseband packet.

The DNPS field 611-3 indicates the number of null TS packets deletedprior to a TS packet group if the number of deleted null TS packets isless than eight (8), and may be implemented by a three (3) bit field. Ifthe number of deleted null packets is more than eight (8), the DNPSfield 611-3 provides a DNP counter field of three (3) LSB bits, and theDNPL field 612-1 provides a DNP counter field of eight (8) MSB bits inthe option header 612.

Meanwhile, the option header 612 of the baseband packet 610 includes theDNPL field 612-1 and an ISSY field 612-2.

As discussed above, the DNPL field 612-1 provides a DNP counter field ofeight (8) MSB bits. Three (3) LSB bits are provided from the DNPS field611-3 of the base header 611. As a result, the DNP counter field mayhave a length of 11 bits at the maximum, and perform signaling to delete2,047 null packets at the maximum in a baseband packet. An eight (8) bitfield may be provided only if the NPD1 field 611-2 is set to “1”, i.e.,if more than eight (8) null packets are deleted prior to the basebandpacket.

The ISSY field 612-2 indicates an input stream clock reference (ISCR)related to a TS packet group in a baseband packet, and may beimplemented by a three (3) byte field. This clock reference may supportreproducing a TS stream through correct timing at a receiving apparatus.The ISSY field 612-2 may be included in the option header 612 of a firstbaseband packet of a baseband frame if an ISSY1 (PLP_ISSY_IND) is set to“1” in L1 signaling regarding a PLP, i.e., when ISSY is activated. Inthis case, all baseband packets within a baseband frame may be delayed,and thus, a same timing reference is requested for all baseband packetsof one same baseband frame.

For example, the ISSY field 612-2 may transmit an ISCR value indicatinga counter value at a moment when a first TS packet included in abaseband packet is input to the baseband packet construction block 1110shown in FIG. 2. Here, the counter is operated at an intervalpredetermined between a transmitting apparatus and a receivingapparatus.

However, the above-described values of each field, e.g., the number ofbits, may be modified so as to be proper for a system operation,according to an exemplary embodiment.

FIGS. 7A to 7D illustrate a baseband packet format according to anotherexemplary embodiment.

Referring to FIGS. 7A to 7D, an NPD byte indicates the number of deletednull packets, or a quotient calculated from dividing the number ofdeleted null packets by 16. In this case, the number of deleted nullpackets (NPDI=10 or 11) may be calculated according to a followingmathematical formula.16*(value of NPD byte)+mod(continuity counter of current TSpacket−continuity counter of previous non-deleted TS packet−1,16)  (1),where mod (x, y) indicates a remainder calculated from dividing x withy.

Referring to FIG. 7A, a TS baseband packet may be formatted such that aone (1) byte header, a payload (without a sync byte) and a one (1) byteoption header including an NPD field 713 are consecutively arranged. Theheader may include an NPDI field 711 of two (2) bits and an NUMTS 712field of six (6) bits.

If the NPDI field 711 is set to a value “11”, the NPD field 713 isallocated at an end of the payload, and indicates a quotient calculatedfrom dividing the number of deleted null packets with 16. The number ofdeleted null packets (NPDI=10 or 11) may be calculated according to theabove-mentioned mathematical formula 1.

Further, a length of the payload may be calculated with NUMTS×187 bytes.

FIG. 7B illustrates a modified exemplary embodiment of FIG. 7A.Referring to FIG. 7B, a TS baseband packet may be formatted such that aone (1) byte header, a one (1) byte option header including an NPD field713 and a payload (without a sync byte) are consecutively arranged.Here, the one (1) byte NPD field may be arranged at a front of thepayload.

Referring to FIG. 7C, a TS baseband packet may be formatted such that aone (1) byte header, a payload (without a sync byte) and a one (1) byteoption header including an NPD field 713 are consecutively arranged.Here, differently from FIG. 7A, an NPDI field 711 may have one (1) bit,and an NUMTS field 712 may have seven (7) bits.

When the NPDI field 711 is set to a value “1”, the NPD field 713 isallocated at an end of the payload, and indicates a quotient calculatedfrom dividing the number of deleted null packets with 16. Here, thenumber of deleted null packets (NPDI=0 or 1) may be calculated accordingto the above-mentioned mathematical formula 1.

FIG. 7D illustrates a modified exemplary embodiment of FIG. 7C.Referring to FIG. 7D, a one (1) byte option header including an NPDfield 713 may be arranged at a front of a payload.

FIGS. 8A to 8F illustrate a baseband packet format according to anotherexemplary embodiment.

Referring to FIGS. 8A to 8D, an SN byte may be allocated for a TSpacket. The SN byte may be allocated at a front of each TS packet in aTS packet stream. Here, the SN byte may have MSB 8 bits regarding a TSsequence number (SN) of the TS packet stream, and a continuity counter(4 bits) in each TS packet may have LSB 4 bits regarding the TS SN.Thus, 12 bits combined with the SN byte and the continuity counter maybe generated.

If a TS stream includes a plurality of packet IDs as a range of thecontinuity counter is determined by a packet ID in a TS packet header,the SN byte becomes a TS SN (8 bits).

The TS SN starts from a predetermined value which increases one by oneregarding each TS packet, reaches to a maximum value, and goes back to“0”. This indicates that the SN byte increases one by one regarding eachof 16 TS packets. When a TS stream includes a plurality of packet IDs asthe range of the continuity counter is determined by a packet ID in a TSpacket header, the SN byte increases one by one regarding each TSpacket.

If deleting a sync byte is activated, the SN byte replaces the syncbyte.

When deleting a null packet is activated, null packets and the SN byteare removed to Z−1.

When an NPD is activated, the number of deleted null packets may becalculated by a following mathematical formula 2.Mod(current TS SN−previous current TS SN−1,Z),when Z=2{circumflex over( )}(size of TS SN(in bits))  (2),where mod (x, y) indicates a remainder calculated from dividing x withy.

If there are TS packets having error or loss between two TS packets, thenumber of error or loss TS packets (to Z−1) may be confirmed from two TSSNs of two TS packets, and a decoder of a receiving apparatus maymaintain a bit rate by replacing a loss TS packet or an error TS packetwith a null packet. Here, the error TS packet indicates a packet inwhich Transport Error Indicator (TEI) is set to a value “1” in a TSpacket header.

Referring to FIG. 8A, combining the SN field 812-1 of a first TS packet813 and a continuity counter (CC) field 812-2 in a TS L2 packetconstitutes a TS SN 812 regarding a TS packet in a TS packet streambefore deleting null packets. Here, the SN field 812-1 may have MSB 8bits, and the CC field 812-2 may have LSB 4 bits.

The number of deleted null packets between two consecutive TS L2 packetsmay be calculated according to a following mathematical formula 3.TS SN for first TS packet of current TS L2 packet−TS SN for first TSpacket of previous TS L2 packet−NUMTS of previous TS L2 packet  (3)

Meanwhile, if a TS L2 packet is lost between two TS L2 packets, thenumber of lost TS packets (maximum 4,096) may be exactly recognized froma difference between two TS SNs regarding two TS L2 packets. Thus, thedecoder may maintain a bit rate by replacing a loss TS packet or anerror TS packet with a null packet.

Referring to FIG. 8B, an NPDI field 814 with one (1) bit in theembodiment of FIG. 8A may be added, and a size of an NUMTS field 811 maybe reduced to be seven (7) bits.

Referring to FIG. 8C, an NPDI field 814 with two (2) bits in theembodiment of FIG. 8A may be added, and a size of an NUMTS field 811 maybe reduced to be six (6) bits.

Referring to FIG. 8D, the embodiment of FIG. 8A or FIG. 8B or FIG. 8Cmay be applied to a first TS L2 packet of an L1 packet. Further, theembodiment of FIG. 7B or FIG. 7D may be applied to another L2 packet(baseband packet) of an L1 packet (baseband frame).

FIGS. 9A to 9H illustrate a baseband packet format according to anotherexemplary embodiment.

Referring to FIGS. 9A to 9H, an L2 packet header may further include aTYPE field 914 indicating a stream time transmitted through a payload.Here, the TYPE field 914 has two (2) bits. An NPDI field 911, an NUMTSfield 912 and an NPD field 913 may have two (2) bits, four (4) bits andeight (8) bits, respectively.

For example, regarding a TS L2 packet, the TYPE field 914 may have avalue “00”.

FIG. 9B illustrates a modified embodiment of FIG. 9A. Referring to FIG.9B, a one (1) byte option header including an NPD field 913 may bearranged at a front of a payload.

Referring to FIG. 9C, an NPDI field 911 may have one (1) bit, and anNUMTS field 912 may have five (5) bits, differently from FIG. 9A.

When the NPDI field 911 is set to a value “1”, the NPD field 913 isallocated at an end of a payload, and indicates a quotient calculatedfrom dividing the number of deleted null packets with 16. Here, thenumber of deleted null packets (NPDI=0 or 1) may be calculated accordingto the above-mentioned mathematical formula 1.

FIG. 9D illustrates a modified embodiment of FIG. 9C. Referring to FIG.9D, a one (1) byte option header including an NPD field 913 may bearranged at a front of a payload.

FIGS. 9E to 9G illustrate exemplary embodiments in which an SN byte fora TS packet is additionally allocated. Each embodiment is similar to theembodiments of FIGS. 8A to 8C, which will not be further explained.

Referring to FIG. 9H, the embodiment of FIG. 9E or FIG. 9F or FIG. 9Gmay be applied to a first TS L2 packet of an L1 packet. Further, theembodiment of FIG. 9B or FIG. 9D may be applied to another TS L2 packetof the L1 packet.

FIG. 10 is a view provided to briefly explain a case in which TS modeadaptation is applied according to various exemplary embodiments.

FIG. 10 illustrates that TS mode adaptation is applied according to theabove various embodiments after allocating a virtual TS SN to each TSpacket of a TS incoming stream.

In this case, TS sync byte deletion may be always applied. However, ifTS sync byte deletion is not applied, an L1 signaling area may indicatewhether to apply sync-removing.

FIG. 11A is a block diagram of a receiving apparatus according to anexemplary embodiment.

Referring to FIG. 11A, the receiving apparatus 200 includes a receiver210 and a signal processor 220.

The receiving apparatus 200 may be implemented to receive data from atransmitting apparatus which maps data in an incoming stream includingonly a first type stream to one or more signal processing paths andtransmits the same. Thus, the receiving apparatus 200 may receive atransmission frame in which only the first type stream is mapped withone or more signal processing paths.

The receiver 210 receives a frame which includes data mapped to one ormore signal processing paths. The receiver 210 may receive a streamwhich includes signaling information and data mapped to one or moresignal processing paths. The signaling information may includeinformation about an input type of an incoming stream received at thetransmitting apparatus and information about a data type mapped to oneor more signal processing paths. The information about an input type ofan incoming stream may indicate whether all signal processing pathswithin the frame is a same input type. The other information included inthe signaling information is described above, which will not be furtherexplained.

The signal processor 220 extracts signaling information from thereceived frame. The signal processor 220 may obtain various pieces ofinformation about a PLP included in an L1 pre-signaling area and an L1post-signaling area by extracting and decoding L1 signaling information.Further, the signal processor 230 may signal-process the frame based onthe extracted and decoded signaling information. For example,signal-processing may perform demodulating, frame de-building, BICMdecoding, and input de-processing.

Specifically, the signal processor 220 generates a baseband frame bysignal-processing the received frame from the receiver 210, and extractsheader information from a plurality of baseband packets included in thebaseband frame.

Further, the signal processor 220 may restore the stream, i.e., theincoming stream described above as being input to the transmittingapparatus by signal-processing payload data included in the basebandpackets based on the extracted header information. The headerinformation may include information about whether the number of nullpackets which are deleted when generating a baseband packet is more thana predetermined number, the number of the first type stream packetswithin the baseband packet, and the number of the deleted null packets.

Here, the first type stream may be a TS or TS stream.

Further, the header may include a base header and an option header asdescribed above.

In this case, the base header may include information about whether thenumber of null packets which are deleted when generating baseband apacket is more than a predetermined number, the number of the first typestream packets within the baseband packet, and the number of nullpackets less than the predetermined number.

Further, the option header may include information about an ISCR relatedto the baseband packet and information about the number of null packetsexceeding the predetermined number when the number of deleted nullpackets is more than the predetermined number.

FIG. 11B is a block diagram provided to explain in detail the signalprocessor according to an exemplary embodiment.

Referring to FIG. 11B, the signal processor 220 includes a demodulator221, a decoder 222 and a stream generator 223.

The demodulator 221 performs demodulation according to OFDM parametersfrom the received RF signals, performs sync-detection, and recognizeswhether the currently received frame from the signaling informationstored in the sync area includes necessary service data when the sync isdetected. For example, the demodulator 221 may recognize whether amobile frame is received or a fixed frame is received.

In this case, if OFDM parameters are not previously determined regardinga signaling area and a data area, the demodulator 221 may performdemodulation by obtaining OFDM parameters regarding the signaling areaand the data area stored in a sync area, and obtaining information aboutOFDM parameters regarding the signaling area and the data area which aredisposed right after the sync area.

The decoder 222 performs decoding of necessary data. In this case, thedecoder 222 may perform decoding by obtaining parameters of an FECmethod and the modulating method regarding the data stored in each dataarea based on the signaling information. Further, the decoder 222 maycalculate positions of necessary data based on the data informationincluded in a configurable field and a dynamic field. Thus, it maycalculate which positions of the frame a requested PLP is transmitted.

The stream generator 223 may generate data to be served by processing abaseband frame input from the decoder 222.

For example, the stream generator 223 may generate a baseband packetfrom the baseband frame in which errors are corrected based on an ISSYmode, buffer size (BUFS), time to output (TTO) values and ISCR values.

Specifically, the stream generator 223 may include de-jitter buffers.The de-jitter buffers may regenerate correct timing to restore an outputstream based on the ISSY mode, BUFS, TTO values and ISCR values.Thereby, a delay for sync between a plurality of PLPs can becompensated.

FIG. 12 is a flowchart provided to explain a signal processing method ofa transmitting apparatus, according to an exemplary embodiment.

According to the signal processing method of the transmitting apparatusillustrated in FIG. 12, a baseband packet including a header and payloaddata corresponding to an incoming first type stream is generated atS1210. Here, the header may include information about whether the numberof null packets deleted when generating a baseband packet is more than apredetermined number, the number of a first type stream packets withinthe baseband packet, and the number of the deleted null packets.

At S1220, a frame including the baseband packet is generated. Here, theframe may be a baseband frame.

At S1230, the generated frame is signal-processed.

At S1240, the signal-processed frame is transmitted. Here, thesignal-processed frame may be a transmission frame.

Here, the first type stream may be a TS stream.

Further, the header may further include information about the ISCRrelated to the baseband packet.

Further, the header may be constituted with a base header and an optionheader. In this case, the base header may include information aboutwhether the number of null packets deleted when generating a basebandpacket is more than a predetermined number, the number the first typestream packets within the baseband packet, and the number of nullpackets less than the predetermined number. Further, the option headermay include information about the ISCR related to the baseband packetand information about the number of null packets exceeding thepredetermined number if the number of deleted null packets is more thanthe predetermined number.

FIG. 13 is a flowchart provided to explain a signal processing method ofa receiving apparatus, according to an exemplary embodiment.

According to the signal processing method of the receiving apparatusreceiving data from a transmitting apparatus which maps data included inan incoming first type stream with one or more signal processing pathsand transmits the same, a frame in which the first type stream is mappedwith one or more signal processing paths is received at S1310.

At S1320, header information is extracted from a baseband packetcorresponding to the first type stream included in the received frame.

At S1330, payload data included in the baseband packet issignal-processed based on the extracted header information. Here, theheader information may include information about whether the number ofnull packets deleted when generating a baseband packet is more than apredetermined number, the number of the first type stream packets withinthe baseband packet, and the number of the deleted null packets.

Here, the first type stream may be a TS or TS stream.

Further, the header information may include information about the ISCRrelated with the baseband packet.

The header includes a base header and an option header, and the baseheader may include information about whether the number of null packetsdeleted when generating a baseband packet is more than a predeterminednumber, the number of the first type stream packets within the basebandpacket, and the number of null packets less than the predeterminednumber. Further, the option header may include information about theISCR related with the baseband packet and information about the numberof null packets exceeding the predetermined number when the number ofdeleted null packets is more than the predetermined number.

Meanwhile, according to some embodiments, null packets disposed prior toa TS packet group may be deleted, but the inventive concept is notlimited thereto. Accordingly, in another exemplary embodiment, the nullpackets disposed after a TS packet group may be deleted.

FIG. 14 is a block diagram of a receiving apparatus according to anexemplary embodiment.

Referring to FIG. 14, the receiving apparatus 1200 may include acontroller 1210, an RF receiver 1220, a demodulator 1230, and a serviceplayer 1240.

The controller 1210 determines an RF channel and a PLP in which aselected service is transmitted. At this process, the RF channel may bedefined by a center frequency and a bandwidth, and the PLP may bedefined by a PLP identifier (ID). Certain services may be transmittedthrough more than one PLP belonging to more than one RF channel percomponent constituting services. However, it is assumed in the followingdescriptions that all data required for playing one service aretransmitted through one PLP with one RF channel for convenientexplanation. Thus, services are provided with a unique data obtainingpath to play services, and the data obtaining path is specified by an RFchannel and a PLP.

The RF receiver 1220 extracts RF signals from a selected RF channel bythe controller 1210, and delivers OFDM symbols, extracted by performingsignal-processing of the RF signals, to the demodulator 1230. The signalprocessing may include synchronization, channel estimation andequalization. Information required for the signal processing ispredetermined between a transmitting and the receiving apparatuses ortransmitted to the receiving apparatus in a predetermined OFDM symbolsamong the OFDM symbols.

The demodulator 1230 extracts a user packet by performing signalprocessing of the OFDM symbols, and delivers to the service player 1240.The service player 1240 plays and outputs the service selected by a userwith the user packet. A format of the user packet may be differentaccording to implementing services. For example, a TS packet or an IPv4packet may be the user packet.

FIG. 15 is a block diagram describing the demodulator 1230 of FIG. 14according to an exemplary embodiment.

Referring to FIG. 15, the demodulator 1230 may include a frame demapper1231, a BICM decoder 1232 for L1 signaling, a controller 1233, a BICMdecoder 1234, and an output processor 1235.

The frame demapper 1231 selects OFDM cells constituting FEC blocksbelonging to a selected PLP from a frame constituted with OFDM symbolsbased on controlling information delivered from the controller 1233, anddelivers to the decoder 1234. Further, the frame demapper 1231 selectsOFDM cells corresponding to more than one FEC block included in L1signaling, and delivers to BICM decoder 1232 for L1 signaling.

The BICM decoder 1232 for L1 signaling signal-processes OFDM cellscorresponding to FEC blocks belonging to L1 signaling, extracts L1signaling bits, and delivers to the controller 1233. In this case, thesignal processing may include extracting log-likelihood ratio (LLR)values for decoding LDPC codes in OFDM cells, and decoding LDPC codes byusing the extracted LLR values.

The controller 1233 extracts an L1 signaling table from L1 signalingbits, and controls operations of the frame demapper 1231, the BICMdecoder 1234, and the output processor 1235 by using values of the L1signaling table. FIG. 11 illustrates that the BICM decoder 1232 for L1signaling does not use controlling information of the controller 1233for convenient explanation. However, if L1 signaling includes a layerstructure similar to the L1 pre-signaling and the L1 post-signalingdescribed above, the BICM decoder 1232 for L1 signaling may beconstituted with more than one BICM decoding block, and operations ofthe BICM decoding blocks and the frame demapper 1231 may be controlledbased on upper-layer L1 signaling information, as clearly understood inthe above description.

The BICM decoder 1234 signal-processes OFDM cells constituting FECblocks belonging to the selected PLP, extracts baseband frames, anddelivers the baseband frames to the output processor 1235. The signalprocessing may include extracting LLR values for coding and decodingLDPC in OFDM cells, and decoding LDPC codes by using the extracted LLRvalues. These two operations may be performed based on the controllinginformation delivered from the controller 1233.

The output processor 1235 signal-processes the baseband frames, extractsa user packet, and delivers the extracted user packet to the serviceplayer. In this case, the signal processing may be performed on thecontrolling information delivered from the controller 1233.

Meanwhile, according to an exemplary embodiment, the output processor1235 may include a baseband packet processor (not illustrated) whichextracts a baseband packet from the baseband frame. Further, a format orconfiguration of the extracted baseband packet is the same as the formataccording to the previous embodiments, e.g., the format illustrated inFIG. 6B (in this case, a PLP transmits a baseband packet having a formatillustrated in FIG. 6B according to L1 signaling). Whether there is aDNPL field (8 bits) is determined from first bit NPDI field informationabout a header of an incoming baseband packet. If an NPDI field is setto a value “0”, the baseband packet processor may restore null TSpackets as many as the number set in the DNPS field (3 bits). If theNPDI field is set to a value “1”, the baseband packet processor mayrestore null TS packets as many as the number set in the DNPS field andthe DNPL field (11 bits), and deliver to the service player 1240.Further, the baseband packet processor may confirm whether to apply anISSY from L1 signaling, whether there is an optional header from valuesof the NPDI, field and a size of the optional header when there is anoptional header. The baseband packet processor may insert a sync byte(0x47) into each of a number of TS packets (187 bytes) as many as thenumber set in an NUMTS field, restore TS packets (187 bytes) and deliverto the service player 1240.

FIG. 16 is a flowchart provided to briefly explain an operation of areceiving apparatus from a time point when a user selects a service to atime point when the selected service is played.

It is assumed that service information about all the services that canbe selected at an initial scan process of S1600 is obtained prior to aservice select process at S1610. The service information may includeinformation about an RF channel and a PLP which transmits data requiredfor playing a specific service in a current broadcasting system. Oneexample of the service information may be Program-SpecificInformation/Service Information (PSI/SI) of an MPEG-2 TS, which may beusually obtained through L2 signaling and an upper layer signaling.

When a user selects a service at S1610, the receiving apparatus modifiesa frequency transmitting the selected service at S1620, and performsextracting RF signals at S1630. While performing S1620 modifying thefrequency transmitting the selected service, the service information maybe used.

When RF signals are extracted, the receiver performs S1640 extracting L1signaling from the extracted RF signals. The receiving apparatus selectsthe PLP transmitting the selected service by using the extracted L1signaling at S1650, and extracts a baseband frame from the selected PLPat S1660. At S1650 selecting the PLP transmitting the selected service,the service information may be used.

Further, S1660 extracting the baseband frame may include selecting OFDMcells belonging to the PLP by demapping a transmission frame, extractingLLR values for coding/decoding LDPC, and decoding LDPC codes by usingthe extracted LLR values.

The receiving apparatus performs S1670 extracting a baseband packet fromthe extracted baseband frame by using header information about theextracted baseband frame, and performs S1680 extracting a user packetfrom the extracted baseband packet by using header information about theextracted baseband packet. The extracted user packet is used in S1690playing the selected service. At S1670 extracting the baseband packetand at S1680 extracting the user packet, L1 signaling informationobtained at S1640 extracting L1 signaling may be used. In this case, aprocess of extracting the user packet from the baseband packet(restoring null TS packet and inserting TS sync byte) is the same asdescribed above.

According to an exemplary embodiment, the L1 signaling includesinformation about a type of a user packet transmitted through acorresponding PLP and an operation used to encapsulate the user packetin the baseband frame. This information may be used at S1680 extractingthe user packet. The user packet is extracted through processes inverseto the operations used in the encapsulating process.

According to an exemplary embodiment, the L1 signaling may also includeinformation about an ISSY mode, information about a buffer size of areceiving apparatus which is requested according to ISSY modeinformation, and information about an output time of a first user packetregarding a corresponding PLP included in a frame. This information maybe used in controlling a buffer at S1680 extracting the user packet.This information may be used to control a size of the buffer storing theextracted user packet and a time when the user packet is output to theservice player.

According to the above various exemplary embodiments, various types ofdata can be mapped to a physical layer that can be transmitted, and adata processing efficiency can be enhanced.

Meanwhile, a non-transitory computer readable recording medium storingprograms to perform the methods described above may be providedaccording to an exemplary embodiment.

The non-transitory computer readable recording medium indicate a mediumwhich store data semi-permanently and can be read by devices, not amedium storing data temporarily such as register, cache, or memory.Specifically, the above various applications or programs may be storedand provided in a non-transitory computer readable recording medium suchas compact disc (CD), digital versatile disk (DVD), hard disk, Blu-raydisk, universal serial memory (USB), memory card, or read-only memory(ROM).

Components, elements or units represented by a block as illustrated inFIGS. 1, 2, 4, 5A, 11A, 11B, 14 and 15 may be embodied as the variousnumbers of hardware, software and/or firmware structures that executerespective functions described above, according to exemplaryembodiments. For example, these components, elements or units may use adirect circuit structure, such as a memory, processing, logic, a look-uptable, etc. that may execute the respective functions through controlsof one or more microprocessors or other control apparatuses. Thesecomponents, elements or units may be specifically embodied by a module,a program, or a part of code, which contains one or more executableinstructions for performing specified logic functions. Also, at leastone of the above components, elements or units may further include aprocessor such as a central processing unit (CPU) that performs therespective functions, a microprocessor, or the like. Further, althoughthe above-mentioned drawings do not illustrate a bus, communicationbetween the components, elements or units may be performed through abus.

The foregoing exemplary embodiments and advantages are merely exemplaryand are not to be construed as limiting the inventive concept. Thepresent teaching can be readily applied to other types of apparatuses.Also, the description of the exemplary embodiments of the presentinventive concept is intended to be illustrative, and not to limit thescope of the claims.

What is claimed is:
 1. A method for generating a packet of atransmitting apparatus, the method comprising: setting a value of aDeleted Null Packet (DNP) counter to zero; increasing the value of theDNP counter for each deleted null packet preceding a non-null transportstream (TS) packet among at least one non-null TS packet; and,generating a packet comprising a header and a payload, wherein theheader comprises a DNP field, wherein the value of the DNP counter isused to set the DNP field, wherein if the value of the DNP counterreaches a maximum allowed value and a next TS packet is a null packet,the null packet is kept as a useful TS packet and encapsulated into thepayload, and wherein the non-null TS packet is a first encapsulatedpacket in the payload.
 2. The method of claim 1, wherein the headercomprises a base header and an additional header, wherein the baseheader comprises a field indicating that a packet type of an inputstream is a TS packet and a field indicating a number of at least onenon-null TS packet included in the packet, and wherein the additionalheader comprises the DNP field.
 3. The method of claim 1, wherein theheader further comprises information about an input stream clockreference (ISCR) related with the packet.